The present invention relates to a dental x-ray diagnostic installation for panoramic tomograms comprising an x-ray source and a holder for a film cassette. The diagnostic device has a common carrier on which the x-ray source is mounted opposite the holder and the carrier moves around the subject by means of a first adjustment mechanism. The film cassette holder has a second adjustment mechanism for moving a film cassette relative to the radiation source during the exposure as well as relative to a slotted diaphragm arranged in the beam path between the source and the film contained in the cassette.
A known apparatus of a dental x-ray diagnostic device is an ORTHOPANTOMOGRAPH 10, which is disclosed in a brochure entitled "Minimize X-Ray dosage Maximumize image quality" WS11843. In the device of this type, the film is inserted into a roughly hemispherically shaped metal cassette and this rigid cassette is then inserted into a holder connected to the carrier. During the exposure, the film cassette is then adjusted relative to the radiation source via a suitable mechanical control means, for example, via cam plates or the like.
In German OS No. 30 05 203, a device is disclosed in which a straight line rigid film cassette is provided instead of the curved film cassette and the cassette is displaced around the subject together with a film cassette holder in accordance with the movement of the radiation source by means of a separate drive. To this end, a slide rail on which a motor driven roller can roll is arranged in the film cassette holder in accordance with the direction of movement of the cassette and the film cassette holder is fashion box-like. A strip-shaped, slide member extends essentially parallel to the slide rail and is seated within the film cassette holder. The motor is driven so that the movement of the holder and film cassette are synchronized with the movement of the x-ray source upon rotation of a swivel arm with the holder and film cassette being continuously displaced in a longitudinal direction of the slide rail.
Rigid film cassettes are first structurally involved and thus increase costs. In addition, there is a disadvantage in manipulation, particularly because the film to be exposed must be inserted into the cassette in a dark room before every exposure. Such a manipulation is especially involved and time consuming, particularly when a plurality of exposures are to be made in succession. Keeping a plurality of prepared cassettes on hand is frequently impossible for reasons of space as well as cost. Size as well as the weight are therefore disadvantages of such a rigid film cassette. In addition, the weight of the film cassette and of the film cassette holder has a disadvantageous effect on the design of the overall drive. The structural size of the cassette and holder has a disadvantageous effect on the freedom to move the cassette and holder. When positioning the patient's head for preparation of the exposure, the film cassette is disturbingly in the way because of being in the field of vision.